1.Field of the Invention
The present invention relates to a hay making machine used for raking and windrowing hay. More particularly, the present invention relates to a rotary-style rake which includes a hydraulically powered lifting mechanism for raising and lowering the rake between working and transporting positions, respectively.
2. Background of the Related Art
In the hay making process, the crop is cut and allowed to dry in the field. Later, the dried crop material has to be raked together in windrows prior to being baled. A farm implement known as a rotary rake is commonly used for such purpose.
A rotary rake comprises a rotary gearbox which rotates a set of rake arms in a rotary fashion about a common axis. The upper side of the gearbox is coupled to the power takeoff (PTO) on the tractor which pulls the rake through the hay field. The gearbox is supported from below by a frame with one or more wheels for transporting the rotary rake. During operation, the rake arms sweep completely around the wheel base of the frame.
To operate the rotary rake in the field, the rake is lowered so that the tips of the rake arms contact the crop. To transport the implement on a roadway, the rake is raised or in some cases disassembled.
A number of rotary style rakes with mechanisms for raising and lowering the machine are known in the prior art. For example, U.S. Pat. No. 3,546,867 relating to a hay harvesting machine, discloses a rotary mechanism 1 rotatably driven about an upright tubular shaft 6. A threaded spindle 40 runs through the center of the tubular shaft 6. By rotating a crank handle 37, the spindle 40 pivots a support frame 32 and tire 31 about fulcrum point 33 to raise or lower the machine. It is also suggested that the spindle 40 may be adjusted by a chain and sprocket drive mechanism which could be operated from the driver seat of the tractor.
U.S. Pat. No. 4,275,552 shows a rotary gearbox which rotates about support shaft 41. Beneath the gearbox is a frame 48 with a series of apertures 49 for locking a wheel arm 50 in any number of selected positions for adjustment of the height of the rotor assembly. When adjusting the height of the rotor assembly, the wheel arm 50 pivots about a transverse axis 51. On the lower end of the wheel arm 50 is wheel 52.
Other kinds of rotary rakes are also disclosed in the prior art. For example, U.S. Pat. No. 4,161,860 shows a rotary rake in which the extending tine carriers 34 rotate about shaft 21, and further shows a ring 47 with a swash plate 42 and universal ball and socket joints 51 and 52 to operate the raking tines. U.S. Pat. No. 4,914,901 shows a rotary gearbox 9 which rotates about a vertical support pin 17 supported by plate 33. U.S. Pat. No. 4,288,972 also shows a gearbox 1 mounted for rotation about a shaft 11. Other rotary raking devices are shown in U.S. Pat. Nos. 3,645,077, 3,832,838, 4,015,412, 4,194,348, 4,875,332, 4,905,466 and 4,976,095.
The difficulty in designing an automated mechanism for raising or lowering the rake is due to the inaccessibility of the underside of the rotary gearbox. As mentioned above, the power coupling is made on the top side of gearbox, while the frame and wheel base support the underside of the gearbox, and the rake arms sweep entirely around the wheel base thereby effectively isolating the upper and lower portions of the machine. There is no easy path to transfer power from above the gearbox to any kind of mechanism that might be located on the support frame below the gearbox.
A further disadvantage with the known devices, such as the hand crank disclosed in U.S. Pat. No. 3,546,867, discussed above, is that the operator must get off the tractor in order to raise or lower the rake. On other devices, the operator may be required to get off the tractor to insert a separate lock pin to secure the implement in the raised position in order to safely transport it on a public roadway.
It would therefore be desirable to provide a rotary rake which has a means for automatically raising and lower the rake so that the operator would not have to leave his seat on the tractor in order to convert the implement from a working position to a transporting position and vice versa. Further, it would be desirable to provide a rotary rake which can be raised and secured into a transport position, again without requiring the operator to leave the seat on the tractor, in order to secure the implement for safe transport down a public roadway.